This invention relates to sailboat masts, and, more particularly, to a sailboat mast which includes a metal lower portion and a non-metal, non-conducting upper portion.
Sailboat masts are conventionally made of metal in order to withstand the variety of forces which are imposed on the mast. The sail exerts substantial bending and torsion forces on the mast, and the bending forces create both tensile and compressive forces along the length of the mast. The mast is supported by shrouds or stays, and substantial stress is created in the area of attachment between the mast and the shrouds.
A metal mast has an inherent risk of electrical conductivity. If a metal mast contacts low-hanging electrical wires, there is a danger that electricity will be conducted by the mast to the boat and its occupants. Notwithstanding this risk, the great majority of masts have continued to be made of metal because non-conductive materials are not strong enough to withstand the forces which are imposed on the mast.
One attempt to avoid the problem of electrical conductivity is described in U.S. Pat. No. 4,291,639. This patent describes a metal mast which is formed in two sections which are joined by an insulating portion. The shrouds are also provided with insulating portions.